This proposal is designed to enhance understanding of the pathways to the PhD among Meyerhoff Scholarship Program (MSP) participants at the University of Maryland, Baltimore County (UMBC), and to develop a more solid causal foundation for claims of the program's impact. The primary program emphasis is to increase the number of underrepresented minority scientists and engineers, especially African American. MSP brings to bear a comprehensive array of supports toward achievement of this goal, including: a comprehensive financial package, contingent upon maintaining a B average in a science, technology, engineering or mathematics (STEM) major;a pre-freshmen year 6-week Summer Bridge Program;full-time advisors who monitor and support students on a regular basis;a family-like social and academic support system;widespread faculty involvement (including as research mentors);and participation in summer research internships. We utilize an array of quantitative and qualitative methods to enhance understanding of why some MSP participants pursue and complete PhDs while others do not (Studies 1 and 2), and to compare the educational outcomes of MSP participants with comparison samples of non-participants (Study 3). Our first specific aim is to test a conceptual model linking pre-college student characteristics to student experience in the MSP and success in college, and in turn, the pathways from these college variables to PhD pursuit and receipt. Structural equation modeling will be used in this aspect of the research. The second specific aim is to provide an exceptionally detailed, real-time exploration of changes in student pathways to the PhD at both the undergraduate and graduate levels. A mixed method, semester-by-semester design will be employed for this aspect of the research. Our third specific aim is to establish stronger causal inferences regarding the efficacy of the Meyerhoff Scholarship Program by using two approaches that avoid many of the potential sources of bias that may be present in past efforts to estimate the impact of the MSP and other intervention strategies with similar goals. Specifically, propensity score matching and a regression discontinuity design will be used for this final aspect of the research. Public Health Relevance Statement: Given the MSP's primary emphasis on increasing the number of underrepresented minority scientists, and the high numbers of African American graduates of the program who have entered and completed science, technology, engineering and mathematics PhDs to date, the findings of the research will have important implications for increased understanding as well as improved programmatic and policy efforts to enhance the number of minority scientists in our nation.